Art has never been so fashionable," declared the author of a new biography of Coco Chanel, Justine Picardie, on a recent edition of Start the Week. "And fashion has never seen itself with quite such seriousness." If you want to see the truth of that statement, look no further than the Royal Academy's latest exhibition, Aware: Art Fashion Identity. Pretentious isn't in it. The show starts with a mission statement: "Clothing is an important marker of individuality and social identity. While fulfilling a practical, and at times protective function, it is also acknowledged as a means of communication, through which elements of personal and collective identities are revealed. Clothing can be effective in celebrating identity and indicating allegiance; for these reasons, it is often subject to suppression and regulation... The artists' particular interpretation uses clothing to explore identity and to speak more broadly of our experience of the world."
Things get worse as you get to the exhibits. An "Artist's Robe" by Grayson Perry, which opens the show as you ascend the stairs of Burlington House, behind the main galleries, is said to refer "to the uniforms associated with society, clubs or academies, while commenting on the position and perception of the artist in contemporary society". An installation by Dai Rees, of leather sewn in animal shapes and called "Carapace: Triptych, The Butcher's Window, 2003", is accompanied by a caption explaining that the detailed "marquetry, which shows scenes of decay in reference to death and trauma, and carries echoes of the branding iron, reinforces the effort and expertise traditionally required to make a piece of clothing, in contrast to much of today's fashion". A double-headed knitted pullover by Rosemarie Trockel "examines the human tendency to form life partnerships, in which we link ourselves to another person. The double figure also suggests the multiple personalities needed to adapt the complexities of modern life".
It is tempting to dismiss all this as truly a case of the Emperor's New Clothes. But it would be a pity. Stripped of all this intellectualisation, the show contains much that is fresh and enjoyable and occasionally revealing.
Whatever it is meant to say about the role of the artist in society, Perry's robe is a genuinely exciting work which uses the weight of fabric and the force of patchwork design with great effect. There is a truly stunning black full-length dress by Susie MacMurray, its surface covered in dressmaker's pins. It is entitled "Widow", but you really don't need the catalogue's interpretation – that it gives "shape to feelings of separation, to a body that has suddenly become tender, to an interior solitude that repels others and condemns the wearer of the dress to painful isolation" – to appreciate a work that communicates glamour and femininity in shape but hardness and painfulness when seen close-up.
Some of the installations are engrossing. A film from 1977 of the artist Marina Abramovic and a male companion standing naked at the entrance to a Bologna Gallery, while fully clothed visitors push between them, is great fun; it makes its point about the body and our embarrassment over it with great wit. There is a very endearing Cindy Sherman from 1975, in which she plays a doll being stripped and clothed. Yoko Ono is here too, filmed inviting an audience to snip off her clothes bit by bit. On the heavier side there is a forceful installation by Kimsooja, concerning the reality faced by cloth workers in Mumbai. Four walls portray aspects of people washing, travelling and sleeping in the mass workhouse that is India's economic miracle.
The trouble with Aware: Art Fashion Identity is partly that modern installation and conceptual art arouses in curators an irresistible urge to explain everything, when the works either succeed (as many do) or fail (as some particularly risible pieces in this show also do) on their own. Trouble is also to be found in the title. This is an exhibition about clothes and identity, necessarily dominated by women artists looking at dress as a symbol of their state and the context in which they live. It is not really about fashion at all, which is a business and a design statement about the self.
"Fashion," Picardie quoted Coco Chanel as saying, "is neither a tragedy nor a painting. It is a charming and ephemeral creation, not an everlasting work of art. Fashion should die and die quickly in order that commerce may survive."
Chanel was being deliberately disingenuous, pricking pretensions. Fashion is design and it is craft. It is also, as Sir Mark Jones, just leaving after a highly successful stint as director of the V&A, put it on Start the Week, "the point at which most people make design decisions for themselves".
There are historical periods – the 20th century above all, but also the Renaissance – when a sweeping art movement spreads itself almost to every art form, from jewellery and coins to textiles and dresses. You only have to see the Diaghilev exhibition at the V&A, one of the highlights of the last year which is now in its last week, to see how eagerly artists from Picasso and Matisse to Cocteau and Bakst took up costume and scenery for the ballet. Freed from figurative art, modern artists felt the draw of clothing the human body with their designs. In vogue or out, fashion is above all about the body as a shape to be flattered and disguised as well as adorned.
In the Royal Academy exhibition, the Japanese designer Yohji Yamamoto is represented by a dress made out of wooden slats. While the caption may waffle on about it being a comment against corsetry the item itself makes the opposite argument, that the female form can be sculpted in hard material as much as soft and still retain its curves. Later this year, Yamamoto is to have a whole show to himself at the V&A. He deserves it. Like Chanel, he is one of the truly great influences and craftspeople of the business.
Yamamoto is also one of the dominant figures of the current exhibition at the Barbican, Future Beauty: 30 Years of Japanese Fashion. Anyone wanting to understand what fashion is about today and the revolution that the Japanese have wrought upon it should hasten to this show. Indeed, anyone who is interested in the Japanese aesthetic as expressed in design and crafts should not miss it. For Japanese design, often praised but too rarely understood, is based fundamentally on craftsmanship, with all the sense of tradition and care with materials that lies behind it.
Yamamoto, along with Kenzo Takada, Issey Miyake and Rei Kawakubo, brought a whole new aesthetic as well as a new look to fashion, turning it into fluid sculpture. These designers made dresses that did not adorn the body; they re-shaped it with daring forms of muted colour, experimental textiles and startling lines. They did it – and are still doing it – because they used a profound knowledge of fabric and design to rework the old in new ways with new materials. Even today, some 40 years after they first came on to the scene, their first designs shock you with their courage.
Fashion is not art. Of course it isn't, in the sense of creating a work to say something significant. But it is craft of the highest order and for all Chanel's cynicism, it can create something enduring.
'Aware: Art Fashion Identity' Royal Academy, London (0844 209 0051; www.royalacademy.org.uk) to 30 January. 'Future Beauty: 30 Years of Japanese Fashion', Barbican, London (020 7638 8891; www.barbican.org.uk) to 6 FebruaryReuse content